The present invention relates to water distillation devices and more particularly to portable units for distilling water in the home using standard household electrical current.
Drinking water available in the home usually contains undesirable contaminants. Various approaches for removing these contaminants have been proposed. Typically, the contaminated water is heated in a closed chamber and vaporized. The hot vapor contains the purified water without the contaminants, which are deposited in the chamber. The vapor is collected and liquified in a cooling condenser to produce clean drinking water. See, for example, U.S. Pat. No. 4,818,344 to Glucksman, dated Apr. 4, 1989 and U.S. Pat. No. 4,342,623 to Loeffler, dated Aug. 3, 1982.
It is desirable that home distillers be energy efficient and easy to maintain. These desires present conflicting options, however, when trying to provide an efficient and easy to clean heating element for the vaporization chamber.
To be energy efficient, the heating element may be placed directly in the water to be vaporized. However, the element is quickly coated with contaminants because of the element's high operating temperature. Complicated maintenance and cleaning procedures to remove the scale of contaminants are usually required. See, for example, Glucksman supra and U.S. Pat. No. 4,612,090 to Ellis, Jr., dated Sept. 16, 1986.
To solve the problem of contaminant scaling, the heating element is often removed from contact with the water to be vaporized by placing it in the vaporization chamber floor. However, the element, because it must heat all the water in the chamber before producing a vapor, is then less energy efficient. See, for example, Loeffler supra, U.S. Pat. No. 4,342,625 to Dennison, dated Aug. 3, 1982, and U.S. Pat. No. 4,081,331 to Weiss, dated Mar. 28, 1978.
The present invention includes a heating element placed directly into the water to be vaporized. In contrast to the prior art, contaminant scaling on the heating element is significantly reduced and the energy efficiency improved by suspending the heating element horizontally just below the water surface level and reducing the element's operating temperature. Because the element is only required to vaporize the thin layer of water above the element, it can operate at a temperature just high enough to vaporize a small amount of water quickly, without heating all of the water in the chamber. A water level regulator maintains the desired water level. A temperature sensor and cut-off switch for the heating element may be provided to prevent overheating due to low water level. The heating element is suspended into the chamber from a removable top which may be displaced by overpressure in the chamber. The top includes all working parts of the distiller, including a condenser operated with household electrical current and control functions. The vaporization chamber may be resistant to scaling and removable for cleaning.
Accordingly, it is an object of the present invention to obviate many of the problems of the prior art and to provide a novel distiller which is energy efficient and easy to clean and maintain.
It is a further object of the present invention to provide a novel distiller in which the heating element heats only a thin layer of water above it with a relatively low temperature to slow the rate of deposit of contaminant material on the heating element.
It is yet another object of the present invention to provide a novel distiller in which the heating element operates at increased efficiency just below the surface of the water to be distilled.
It is still another object of the present invention to provide a novel method for distilling water in which efficiency is improved by suspending the heating element just below the water surface.